The object of this proposed research is to determine what the composition of growth (i.e., fat vs. lean weight) is in newborn infants and to determine whether this body composition can be affected by feeding either human milk, cow milk formula or soy formula. A further objective is to study the resting metabolic rates in these infants as it relates to their lean body mass to account for apparent variations in metabolic rates in newborns noted by others. Body composition will be determined through the use of a new instrument called an EMME, which until recently has been used only to measure the fatness of farm animals. This non-invasive instrument operates on the principle that organisms placed in an electro-magnetic field perturb the field, the degree of which is dependent upon the amount of conducting material (electrolyte) present, which resides almost exclusively in the lean compartment. Metabolic rates will be determined with a Noyon's diaferometer which simultaneously measures O2 consumed and CO2 produced by the infant in a non-invasive manner. Not only will this study afford the opportunity to determine metabolic rate in a newborn population whose body composition has been defined but since metabolic rate is directly proportional to lean weight, it can be used to assess the accuracy of the EMME.